Energetic Charged Particles Above Thunderclouds

Abstract

International audienceThe French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth's atmosphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C.T.R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terrestrial gamma-ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth's atmosphere to propose areas of future research. The report specifically reflects presentations delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The scientific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth's atmosphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized

Illumination of mesospheric irregularity by lightning discharge

“…The agreement between the quasi-static electric field and the high-level discharge activity is excellent (Figure 4, top left and center left panels). A similar example of a high-level discharge activity superimposed on a quasi-static electric field (Figure 4, top right and center right panels) was observed in association with an extremely well-documented example of two consecutive lightning discharges [Füllekrug et al, 2013b]. The source locations of the pulses occurring during the second lightning discharge have been mapped with an array of radio receivers [Mezentsev and Füllekrug, 2013] which shows that their origin are intracloud lightning discharges at an average height of 3.5 km (Figure 4, bottom).…”

“…One possible mechanism could be for example electron pileup during which the positive cloud‐to‐ground discharge dislocates electrons with the heavier ions following later to neutralize the electric field produced by the dislocated electrons. Such kind of mechanism could be in operation, for example, if hydrometeors [ Gurevich et al , ; Gurevich and Karashtin , ] or aerosols [ Füllekrug et al , , ] contribute significantly to the observed quasi‐static electric field.…”

Array analysis of electromagnetic radiation from radio transmitters for submarine communication

“…As a result, this contribution aims to determine the wave number vectors by use of an array of radio receivers. Specifically, the array analyses developed for seismic and infrasound arrays [e.g., Füllekrug et al, 2013c;Rost and Thomas, 2002;Gaffet et al, 1998;Cansi, 1995] are adapted and subsequently exemplarily applied to ∼20-24 kHz radio waves from radio transmitters for submarine communication to validate the array analysis.…”

Toward an Improved Representation of Middle Atmospheric Dynamics Thanks to the ARISE Project

“…Infrasound is an innovative technique for monitoring continuously the infrasound signals produced by lightning and TLEs in tropical regions where there are no groundbased current observations. They will be very useful for the validation of observation from space of future space mission as TARANIS (Blanc et al 2007;Lefeuvre et al 2008), ASIM (Neubert et al 2009) and associated studies (Füllekrug et al 2013). ARISE will provide a unique database and will contribute to their monitoring in the longer term.…”